SCOAR is a regionally coupled ocean-atmosphere model, developed by H. Seo as part of his Ph.D. thesis at the Scripps Institution of Oceanography, UCSD.

Development of SCOAR is motivated by the fact that climate models continue to have difficulties simulating the mean climate despite the significant improvement in numerical resolution and representation of physical processes. Some fundamental processes are poorly resolved in these models, including the SST variation associated with the ocean dynamics and the coupling of air-sea boundary layers. These presses are better resolved in the regional coupled models.

Unlike many currently available regional coupled modeling system applied to the climate studies, SCOAR, one of its first kind, is based on a very simple input-output coupler. This file-coupling strategy becomes an extremely convenient method for building coupled modeling when it comes to update/addition of new ocean/atmosphere modeling components. This is because it requires no significant knowledge of the internal structure of the individual models as well as software-engineering skill to modify to construct for model coupling. However one should eventually feel fluent in using/modifying the model to be able to produce the best results from the coupled model. The SCOAR hence allows users to spend more time in analyzing coupled model results without significant investment in time and efforts for technical modeling coupling.

One of the disadvantages in file-coupling is that the coupler can be computationally inefficient if a large re-gridding is needed with high coupling frequency. In the past applications, the SCOAR coupler has shown to be very efficient (typically <5% of total cpu time). The efficiency in coupling is also aided by choosing the identical model grids in the ocean and atmosphere, which comes with an added benefit that the oceanic forcing of the atmosphere is best achieved with the eddy resolving ocean model coupled to the atmosphere with matching grid.

Coupler also should conserve mass and energy, which is achieved with the most use of the individual model physics to calculate the variables for coupling (i.e., atmospheric surface forcing from the atmospheric nonlocal boundary layer physics), which also ensure consistency in flux between the ocean and atmosphere.

The SCOAR model is extremely portable, which can be applied to many different regions of global oceans, making it an ideal tool to study process-modeling of coupled air-sea interactions.

SCOAR is originally coupled ROMS to RSM (SCOAR1);

SCOAR2 (funded in part by ONR) couples ROMS to WRF model to study tropical intraseasonal oscillations in a tropical channel configuration (see the SCOAR2 presentation file).